1. Field of the Invention
The present invention generally relates to medical devices, and more so specifically relates to medical devices, systems and methods for relieving pressure sores.
2. Description of the Related Art
Pressure sores result when body parts, such as heels, ankles, tailbones, buttocks, or hips, rub against surfaces such as mattresses, bed sheets, and wheel chairs. Pressure sores are not only very painful, but they are also prone to infection, which can spread to the bones and blood stream.
FIGS. 1A-1D show the different points where pressure sores may occur when patients are supported in different positions. The spots on the patient shown in FIGS. 1A-1D indicate where the pressure sores are most likely to occur.
There are four different stages of pressure sores, with stage I being the mildest and stage IV being the worst. Referring to FIGS. 2A and 2B, in stage I, the skin is intact with non-blanchable redness of a localized area usually over a bony protuberance. Darkly pigmented skin may not have visible blanching, however, its color may differ from the surrounding area. Referring to FIGS. 3A and 3B, during stage II, there is a partial thickness loss of the dermis or upper layer of the skin presenting as a shallow open ulcer with a red or pink wound bed, without sloughing. Symptoms may also include an intact or ruptured serum-filled blister.
FIGS. 4A and 4B show stage III whereby there is a full thickness tissue loss. Subcutaneous fat may be visible but bone, tendon and muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. There may also be undermining and tunneling, whereby the wound infection tunnels under the healthy skin. Referring to FIGS. 5A and 5B, in stage IV there is full thickness tissue loss with exposed bone, tendon and muscle. Slough or eschar may be present on some parts of the wound bed. There may also be undermining and tunneling whereby the wound infection tunnels under the healthy skin.
Those who are most vulnerable to pressure sores are the elderly, stroke victims, patients with diabetes, those with dementia, individuals who use wheelchairs, bedridden patients, and patients with impaired mobility or sensation. Pressure sores typically occur when patients lay on pressure spots such the heels, buttocks, spine, elbows, shoulders and sometimes the head. In some instances, pressure sores may develop in as little as two hours. Pressure sores typically result from prolonged periods of uninterrupted pressure on the skin, soft tissue, muscle and bone.
There are a number of techniques that have been developed for minimizing the likelihood of pressure sores. First, medical personnel can change the position of the patient every two hours, or, if able, the patient can change his or her position. Medical personnel may also check for redness or sores on the skin to help locate pressure sores as early as possible. In addition, medical personnel also maintain the skin as dry as possible. In spite of the above efforts, over a quarter million patients a year suffer pressure sores in stages three and four.
Unfortunately, nurses and medical personnel do not have sufficient time to move patients for minimizing the likelihood of pressure sores. One study found that if medical personnel spent 30-40 minutes a day moving and/or adjusting the position of a patient, the occurrence of pressure sore cases would be reduced by about 300 percent.
In 2007, Medicare data showed that there were over one-quarter of a million cases of pressure sores in the United States. A public health and environment survey for the years 1990-2000 showed that pressure sore cases resulted in approximately 105,7034 deaths. According to one study, the average cost of a hospital stay for treating pressure sores was $43,180.00.
At present, there are a number of systems, devices and methods for minimizing pressure sores. For example, air pressure reducing mattresses, sheepskin, water beds, and sand beds have been used for minimizing pressure sores. U.S. Patent Publication No. 2007/0056101 discloses a system for detecting conditions to prevent a bedsore including a first sensor to detect a first condition that results in the bedsore and to output a first sensor signal from the first sensor indicative of the first condition that results in the bedsore, a controller to receive the first sensor signal and to determine if the condition may result in the bedsore and an alarm responsive to the controller to provide an alarm to indicate that the condition may result in the bedsore. U.S. Pat. No. 6,287,253 discloses a similar type of system for detecting bed sores. In spite of these advances, there remains a need for medical devices, systems and methods that are able to both detect circumstances where pressure sores are likely to occur and that automatically respond for minimizing the likelihood of pressure sores.